------------[ cut here ]------------ WARNING: CPU: 1 PID: 64 at lib/percpu-refcount.c:112 __percpu_ref_exit+0x98/0x100 lib/percpu-refcount.c:112 Modules linked in: CPU: 1 PID: 64 Comm: kworker/u4:2 Not tainted 5.10.96 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014 Workqueue: events_unbound io_ring_exit_work RIP: 0010:__percpu_ref_exit+0x98/0x100 lib/percpu-refcount.c:112 Code: ff 49 8d 7c 24 10 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 75 61 49 83 7c 24 10 00 74 07 e8 b8 d8 50 ff <0f> 0b e8 b1 d8 50 ff 48 89 ef e8 b9 40 6c ff 48 89 da 48 b8 00 00 RSP: 0018:ffff88800f2c7bf8 EFLAGS: 00010293 RAX: 0000000000000000 RBX: ffff888044504000 RCX: ffffffff81eec8c8 RDX: ffff888008e7b280 RSI: ffffffff81eec928 RDI: ffff88804489b990 RBP: 0000607f92e0be60 R08: 0000000000000001 R09: ffffffff865556e7 R10: 0000000000000000 R11: 0000000000000001 R12: ffff88804489b980 R13: ffff888043d59940 R14: ffff88804489b980 R15: dead000000000122 FS: 0000000000000000(0000) GS:ffff88806cf00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fcbd0596718 CR3: 00000000457a2000 CR4: 0000000000350ee0 Call Trace: percpu_ref_exit+0x3b/0x140 lib/percpu-refcount.c:133 io_ring_ctx_free fs/io_uring.c:8466 [inline] io_ring_exit_work+0x60f/0x920 fs/io_uring.c:8543 process_one_work+0x9a9/0x1590 kernel/workqueue.c:2279 worker_thread+0x61d/0x1310 kernel/workqueue.c:2425 kthread+0x38f/0x470 kernel/kthread.c:313 ret_from_fork+0x22/0x30 arch/x86/entry/entry_64.S:296 irq event stamp: 1505103 hardirqs last enabled at (1505113): [] console_unlock+0x929/0xb30 kernel/printk/printk.c:2559 hardirqs last disabled at (1505122): [] console_unlock+0x835/0xb30 kernel/printk/printk.c:2474 softirqs last enabled at (1505090): [] asm_call_irq_on_stack+0x12/0x20 softirqs last disabled at (1505083): [] asm_call_irq_on_stack+0x12/0x20 ---[ end trace b5ea4aaca73dc83b ]--- ================================================================== BUG: KASAN: use-after-free in rcu_cblist_dequeue+0xa4/0xe0 kernel/rcu/rcu_segcblist.c:75 Read of size 8 at addr ffff88804489b9a0 by task ksoftirqd/1/16 CPU: 1 PID: 16 Comm: ksoftirqd/1 Tainted: G W 5.10.96 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x107/0x163 lib/dump_stack.c:118 print_address_description.constprop.0+0x1c/0x210 mm/kasan/report.c:385 __kasan_report mm/kasan/report.c:545 [inline] kasan_report.cold+0x37/0x7c mm/kasan/report.c:562 rcu_cblist_dequeue+0xa4/0xe0 kernel/rcu/rcu_segcblist.c:75 rcu_do_batch kernel/rcu/tree.c:2475 [inline] rcu_core+0x4a3/0x1660 kernel/rcu/tree.c:2722 __do_softirq+0x1b8/0x867 kernel/softirq.c:298 run_ksoftirqd kernel/softirq.c:653 [inline] run_ksoftirqd+0x21/0x50 kernel/softirq.c:645 smpboot_thread_fn+0x3f5/0x860 kernel/smpboot.c:164 kthread+0x38f/0x470 kernel/kthread.c:313 ret_from_fork+0x22/0x30 arch/x86/entry/entry_64.S:296 Allocated by task 7304: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 kasan_set_track mm/kasan/common.c:56 [inline] __kasan_kmalloc.constprop.0+0xc2/0xd0 mm/kasan/common.c:461 kmalloc include/linux/slab.h:552 [inline] kzalloc include/linux/slab.h:664 [inline] percpu_ref_init+0xd8/0x390 lib/percpu-refcount.c:75 io_ring_ctx_alloc fs/io_uring.c:1205 [inline] io_uring_create fs/io_uring.c:9414 [inline] io_uring_setup+0x660/0x2ef0 fs/io_uring.c:9557 do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Freed by task 64: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 kasan_set_track+0x1c/0x30 mm/kasan/common.c:56 kasan_set_free_info+0x1b/0x30 mm/kasan/generic.c:355 __kasan_slab_free+0x110/0x150 mm/kasan/common.c:422 slab_free_hook mm/slub.c:1542 [inline] slab_free_freelist_hook+0xa9/0x180 mm/slub.c:1576 slab_free mm/slub.c:3149 [inline] kfree+0xd7/0x380 mm/slub.c:4125 percpu_ref_exit+0xf7/0x140 lib/percpu-refcount.c:144 io_ring_ctx_free fs/io_uring.c:8466 [inline] io_ring_exit_work+0x60f/0x920 fs/io_uring.c:8543 process_one_work+0x9a9/0x1590 kernel/workqueue.c:2279 worker_thread+0x61d/0x1310 kernel/workqueue.c:2425 kthread+0x38f/0x470 kernel/kthread.c:313 ret_from_fork+0x22/0x30 arch/x86/entry/entry_64.S:296 Last call_rcu(): kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 kasan_record_aux_stack+0x9e/0xb0 mm/kasan/generic.c:346 __call_rcu kernel/rcu/tree.c:2963 [inline] call_rcu+0x8a/0xa00 kernel/rcu/tree.c:3037 __percpu_ref_switch_to_atomic lib/percpu-refcount.c:226 [inline] __percpu_ref_switch_mode+0x3a1/0x810 lib/percpu-refcount.c:273 percpu_ref_kill_and_confirm+0x8a/0x180 lib/percpu-refcount.c:387 percpu_ref_kill include/linux/percpu-refcount.h:149 [inline] io_ring_ctx_wait_and_kill+0x84/0x600 fs/io_uring.c:8559 io_uring_release+0x3e/0x50 fs/io_uring.c:8604 __fput+0x285/0x980 fs/file_table.c:281 task_work_run+0xe2/0x1a0 kernel/task_work.c:151 exit_task_work include/linux/task_work.h:30 [inline] do_exit+0xc1b/0x2770 kernel/exit.c:811 do_group_exit+0x125/0x310 kernel/exit.c:908 get_signal+0x469/0x2200 kernel/signal.c:2748 arch_do_signal+0x88/0x1b70 arch/x86/kernel/signal.c:805 exit_to_user_mode_loop kernel/entry/common.c:161 [inline] exit_to_user_mode_prepare+0xf7/0x160 kernel/entry/common.c:191 syscall_exit_to_user_mode+0x38/0x230 kernel/entry/common.c:266 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Second to last call_rcu(): kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 kasan_record_aux_stack+0x9e/0xb0 mm/kasan/generic.c:346 __call_rcu kernel/rcu/tree.c:2963 [inline] call_rcu+0x8a/0xa00 kernel/rcu/tree.c:3037 __percpu_ref_switch_to_atomic lib/percpu-refcount.c:226 [inline] __percpu_ref_switch_mode+0x3a1/0x810 lib/percpu-refcount.c:273 percpu_ref_kill_and_confirm+0x8a/0x180 lib/percpu-refcount.c:387 percpu_ref_kill include/linux/percpu-refcount.h:149 [inline] __io_uring_register fs/io_uring.c:9740 [inline] __do_sys_io_uring_register+0x499/0x3f40 fs/io_uring.c:9881 do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 The buggy address belongs to the object at ffff88804489b980 which belongs to the cache kmalloc-64 of size 64 The buggy address is located 32 bytes inside of 64-byte region [ffff88804489b980, ffff88804489b9c0) The buggy address belongs to the page: page:00000000ab348939 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x4489b flags: 0x100000000000200(slab) raw: 0100000000000200 dead000000000100 dead000000000122 ffff888007c418c0 raw: 0000000000000000 0000000000200020 00000001ffffffff ffff88800e720001 page dumped because: kasan: bad access detected page->mem_cgroup:ffff88800e720001 Memory state around the buggy address: ffff88804489b880: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ffff88804489b900: 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc >ffff88804489b980: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ^ ffff88804489ba00: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ffff88804489ba80: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ================================================================== BUG: unable to handle page fault for address: ffffde2016939600 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 7c2a067 P4D 7c2a067 PUD 0 Oops: 0000 [#1] SMP KASAN NOPTI CPU: 1 PID: 16 Comm: ksoftirqd/1 Tainted: G B W 5.10.96 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014 RIP: 0010:percpu_ref_switch_to_atomic_rcu+0xcb/0x3a0 lib/percpu-refcount.c:175 Code: c0 66 a8 84 48 89 fa 48 c1 ea 03 80 3c 2a 00 0f 85 67 02 00 00 4a 8b 04 ed c0 66 a8 84 4c 01 e0 48 89 c2 49 89 c5 48 c1 ea 03 <80> 3c 2a 00 0f 85 52 02 00 00 49 03 5d 00 e8 f2 ce 50 ff 44 89 ff RSP: 0018:ffff8880085afcb0 EFLAGS: 00010216 RAX: ffff1100b49cb000 RBX: 0000000000000000 RCX: ffffffff81eed327 RDX: 1fffe22016939600 RSI: ffffffff81eed2aa RDI: ffffffff84a866c0 RBP: dffffc0000000000 R08: 0000000000000000 R09: ffffffff8547328f R10: 0000000000000000 R11: 0000000000000001 R12: ffff888047bcb000 R13: ffff1100b49cb000 R14: ffff88804489b9a0 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff88806cf00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffde2016939600 CR3: 0000000042de4000 CR4: 0000000000350ee0 Call Trace: rcu_do_batch kernel/rcu/tree.c:2485 [inline] rcu_core+0x52d/0x1660 kernel/rcu/tree.c:2722 __do_softirq+0x1b8/0x867 kernel/softirq.c:298 run_ksoftirqd kernel/softirq.c:653 [inline] run_ksoftirqd+0x21/0x50 kernel/softirq.c:645 smpboot_thread_fn+0x3f5/0x860 kernel/smpboot.c:164 kthread+0x38f/0x470 kernel/kthread.c:313 ret_from_fork+0x22/0x30 arch/x86/entry/entry_64.S:296 Modules linked in: CR2: ffffde2016939600 ---[ end trace b5ea4aaca73dc83c ]--- RIP: 0010:percpu_ref_switch_to_atomic_rcu+0xcb/0x3a0 lib/percpu-refcount.c:175 Code: c0 66 a8 84 48 89 fa 48 c1 ea 03 80 3c 2a 00 0f 85 67 02 00 00 4a 8b 04 ed c0 66 a8 84 4c 01 e0 48 89 c2 49 89 c5 48 c1 ea 03 <80> 3c 2a 00 0f 85 52 02 00 00 49 03 5d 00 e8 f2 ce 50 ff 44 89 ff RSP: 0018:ffff8880085afcb0 EFLAGS: 00010216 RAX: ffff1100b49cb000 RBX: 0000000000000000 RCX: ffffffff81eed327 RDX: 1fffe22016939600 RSI: ffffffff81eed2aa RDI: ffffffff84a866c0 RBP: dffffc0000000000 R08: 0000000000000000 R09: ffffffff8547328f R10: 0000000000000000 R11: 0000000000000001 R12: ffff888047bcb000 R13: ffff1100b49cb000 R14: ffff88804489b9a0 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff88806cf00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffde2016939600 CR3: 0000000042de4000 CR4: 0000000000350ee0 ---------------- Code disassembly (best guess): 0: c0 66 a8 84 shlb $0x84,-0x58(%rsi) 4: 48 89 fa mov %rdi,%rdx 7: 48 c1 ea 03 shr $0x3,%rdx b: 80 3c 2a 00 cmpb $0x0,(%rdx,%rbp,1) f: 0f 85 67 02 00 00 jne 0x27c 15: 4a 8b 04 ed c0 66 a8 mov -0x7b579940(,%r13,8),%rax 1c: 84 1d: 4c 01 e0 add %r12,%rax 20: 48 89 c2 mov %rax,%rdx 23: 49 89 c5 mov %rax,%r13 26: 48 c1 ea 03 shr $0x3,%rdx * 2a: 80 3c 2a 00 cmpb $0x0,(%rdx,%rbp,1) <-- trapping instruction 2e: 0f 85 52 02 00 00 jne 0x286 34: 49 03 5d 00 add 0x0(%r13),%rbx 38: e8 f2 ce 50 ff callq 0xff50cf2f 3d: 44 89 ff mov %r15d,%edi